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	hartrees
Energy at 0K	-154.483548
Energy at 298.15K	-154.486623
HF Energy	-154.483548
Nuclear repulsion energy	98.982038

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3292	3138	0.00
2	A_g	1670	1592	0.00
3	A_g	1137	1084	0.00
4	A_g	982	935	0.00
5	A_u	881	839	0.00
6	A_u	542	517	0.00
7	B_1g	858	818	0.00
8	B_1u	3281	3128	24.28
9	B_1u	1682	1603	2.21
10	B_1u	1073	1022	0.44
11	B_2g	595	567	0.00
12	B_2u	3260	3107	12.57
13	B_2u	1280	1220	36.56
14	B_2u	746	711	7.97
15	B_3g	3243	3091	0.00
16	B_3g	1191	1135	0.00
17	B_3g	840	801	0.00
18	B_3u	595	567	128.88

Atom	y (Å)	z (Å)
C1	0.666	0.784
C2	0.666	-0.784
C3	-0.666	0.784
C4	-0.666	-0.784
H5	1.438	1.546
H6	1.438	-1.546
H7	-1.438	1.546
H8	-1.438	-1.546

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5683	1.3323	2.0578	1.0840	2.4541	2.2374	3.1391
C2	1.5683		2.0578	1.3323	2.4541	1.0840	3.1391	2.2374
C3	1.3323	2.0578		1.5683	2.2374	3.1391	1.0840	2.4541
C4	2.0578	1.3323	1.5683		3.1391	2.2374	2.4541	1.0840
H5	1.0840	2.4541	2.2374	3.1391		3.0911	2.8753	4.2217
H6	2.4541	1.0840	3.1391	2.2374	3.0911		4.2217	2.8753
H7	2.2374	3.1391	1.0840	2.4541	2.8753	4.2217		3.0911
H8	3.1391	2.2374	2.4541	1.0840	4.2217	2.8753	3.0911

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.622
C1	C3	C4	90.000	C1	C3	H7	135.378
C2	C1	C3	90.000	C2	C1	H5	134.622
C2	C4	C3	90.000	C3	C1	H5	135.378
C4	C2	H6	135.378	C4	C3	H7	134.622

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: PBE1PBE/6-31G**

States and conformations

	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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Number	Element	Mulliken
1	C	-0.172
2	C	-0.172
3	C	-0.172
4	C	-0.172
5	H	0.172
6	H	0.172
7	H	0.172
8	H	0.172

<r²>	57.355
(<r²>)^1/2	7.573

All results from a given calculation for C4H4 (cyclobutadiene)

using model chemistry: PBE1PBE/6-31G**

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)